CODEWITHSUNDEEP
androidandroid-activityandroid-library
pz64_
pz64_

Reputation: 2252

Android - Prevent activity from restarting after staying in background

I'm developing a library which consist of 4 activities [A,B,C,D]

Activity A is launched by user-app
    A launches B and expect response on `onActivityResult`.
        B finishes by setting RESULT_OK
    A launches C and expect response on `onActivityResult`.
        C do some Image processing on a 4096x2160 image and finishes by setting RESULT_OK
    A launches D and expect response on `onActivityResult`.
        D finishes by setting RESULT_OK
    A set it's result as  RESULT_OK finishes.
The result is returned to the user-app.

The problem occures after this step C do some Image processing on a 4096x2160 image and finishes by setting RESULT_OK

after that step, the activity A is destroyed from behind and onCreate in A is called i.e A launches B and expect response on onActivityResult. is called again. How can I do this in a better way so that there won't be any surprise shutdowns.

Here is the code of actiivity A:

class  SelectPackage : AppCompatActivity() {

companion object {

    internal const val RES_PACKAGE_CANCEL = 100
    internal const val RES_PACKAGE_OK = 104
    internal const val RES_EDITACTIVITY_CANCEL = 101
    internal const val RES_EDITACTIVITY_OK = 105
    internal const val RES_SUMMARY_CANCEL = 102
    internal const val RES_SUMMARY_OK = 103
}

private val REQ_CODE = 1023

private val data: Data by lazy { makeDataObject() }

private fun makeDataObject(): Data {
    val data = Data()

    data.clientToken = intent.getStringExtra(clientToken)
    ....
    ....
    data.screenSize = intent.getStringExtra(screenSize)

    return data
}

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_select_package)

    Log.d("YYY", "Activity started again")
    val i = Intent(this, Packages::class.java)
    i.putExtra(SelectPackage.DATA, data)

    startActivityForResult(i, REQ_CODE)

}

override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
    super.onActivityResult(requestCode, resultCode, data)
    if (requestCode == REQ_CODE) {
        when (resultCode) {

            RES_PACKAGE_CANCEL -> {
                setResult(AppCompatActivity.RESULT_CANCELED)
                finish()
            }

            RES_PACKAGE_OK -> {
                if (data != null) {
                    val intent = Intent(this, EditActivity::class.java)
                    intent.putExtra(SelectPackage.DATA, data.getSerializableExtra(SelectPackage.DATA))
                    intent.putExtra(Pkgs.TAG, data.getSerializableExtra(Pkgs.TAG))
                    startActivityForResult(intent, REQ_CODE)
                }
            }

            RES_EDITACTIVITY_CANCEL -> {
                setResult(AppCompatActivity.RESULT_CANCELED)
                finish()
            }

            RES_EDITACTIVITY_OK -> {
                if (data != null) {
                    val intent = Intent(this, SummaryActivity::class.java)
                    intent.putExtra(SelectPackage.DATA, data.getSerializableExtra(SelectPackage.DATA))
                    intent.putExtra(Pkgs.TAG, data.getSerializableExtra(Pkgs.TAG))
                    startActivityForResult(intent, REQ_CODE)
                }
            }

            RES_SUMMARY_CANCEL -> {
                setResult(AppCompatActivity.RESULT_CANCELED)
                finish()
            }

            RES_SUMMARY_OK -> {
                if (data != null) {
                    val intent = Intent()
                    intent.putExtra(SelectPackage.packageName, data.getStringExtra(SelectPackage.packageName))
                    intent.putExtra(SelectPackage.packageId, data.getStringExtra(SelectPackage.packageId))
                    intent.putExtra(SelectPackage.packagePrice, data.getFloatExtra(SelectPackage.packagePrice,0f))
                    setResult(AppCompatActivity.RESULT_OK)
                    finish()
                }
            }
        }

    }
}

}

Upvotes: 2

Views: 682

Answers (1)

Liar
Liar

Reputation: 1255

Lack of RAM causes OS to kill your Activity A's process (take a look at this). Maybe you are doing too much in Activity C's process.

A workaround can be storing your results to local storage (Example: SharedPreferences). In onCreate() of Activity A, check the local storage to decide what to do next.

Upvotes: 2

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